Anemia Management in Pregnancy Quiz

Presenting Problems in Blood Disease

• Anemia is a condition where hemoglobin levels in the blood fall below the normal range for age and sex.
• Pregnancy's increased plasma volume dilutes hemoglobin, decreasing reference ranges to > 105 g/L at 28 weeks.
• Mean Cell Volume (MCV) can increase by 5 fL during pregnancy.
• Progressive neutrophilia occurs.
• Gestational thrombocytopenia, rarely below 60 x 10⁹/L, is a benign phenomenon.
• Altitude affects hemoglobin levels, and must be considered when determining anemia.

Learning Objectives

• Define, categorize, and classify causes of anemia.
• Describe the clinical presentation of anemia.
• Outline the investigation and approach to anemia.
• Detail the causes of iron deficiency anemia (IDA), and its diagnostic methods.
• Explain iron absorption, regulation, and distribution in the body.
• List the differential diagnosis and treatment of IDA.

Clinical Features of Anemia

• Clinical features of anemia reflect diminished oxygen supply to tissues and depend on:
  • Severity of anemia
  • Rate of development
  • Presence of cardiorespiratory disease
• Rapid-onset anemia (e.g., blood loss) causes more severe symptoms than gradually developing anemia. Individuals with cardiorespiratory issues experience symptoms at higher hemoglobin levels compared to those with healthy cardiopulmonary function.

Diagnosis of Anemia

• Diagnosis involves clinical history, physical exam, full blood count, blood film analysis, and appropriate additional investigations.

History

• Iron deficiency anemia is the most common type worldwide.
• Comprehensive gastrointestinal history is crucial for blood loss identification.
• Severe menstrual bleeding (menorrhagia) is a frequent cause of anemia in menstruating females.
• Dietary history assesses iron and folate intake, particularly considering pregnancy or rapid growth periods.

Past Medical History

• Past medical history can reveal conditions associated with anemia, such as rheumatoid arthritis, or surgical procedures (e.g., stomach or small bowel resection) affecting iron or vitamin B12 absorption.
• Family history helps identify inheritable blood disorders like haemoglobinopathies or hereditary spherocytosis.

Physical Examination

• General physical findings for anemia.
• Specific physical findings may indicate underlying causes, such as right iliac fossa mass in caecal carcinoma cases.
• Haemolytic anaemia can cause jaundice.
• Vitamin B12 deficiency often presents with neurological issues such as peripheral neuropathy, dementia, or subacute combined degeneration of the spinal cord.
• Sickle-cell anaemia may result in leg ulcers.
• Absent or nonspecific symptoms do not necessarily rule out underlying pathologies.

Classification of Causes

• Decreased or ineffective marrow production: Iron, vitamin B12 or folate deficiency, hypoplasia (reduced cell development), malignant cell infiltration, or renal failure.
• Peripheral causes: Blood loss, hemolysis (red blood cell destruction), hypersplenism (overactive spleen destroying blood cells).

Investigation Schemes

• Investigation schemes for anemia often center on red blood cell size (Mean Cell Volume or MCV).
• A normal MCV (normocytic anemia) suggests either acute blood loss or anemia of chronic disease (ACD).
• Low MCV (microcytic anemia) suggests iron deficiency or thalassemia.
• High MCV (macrocytic anemia) suggests B12 or folate deficiency.

Reticulocyte Count

• Reticulocyte counts distinguish between anemia due to reduced red blood cell production versus increased red blood cell destruction.
• Reticulocytes, immature red blood cells still containing RNA, are detectable with staining.
• The reticulocyte count reflects the bone marrow response to anemia.

Iron Deficiency Anemia (IDA)

• Prevalence: Around 30% of the global population is anemic and about half of these have iron deficiency anemia (IDA).
• Importance of Iron: Iron is critical for diverse biological functions, including oxygen transport and respiration, and nearly half of the enzymes in the Krebs cycle contain or need iron.
• Iron Absorption: The average mixed diet contains 10-20 mg of iron daily with only 5-10% being absorbed. Iron absorption is predominantly in the duodenum and jejunum after releasing it from protein complexes through acid and proteolytic enzymes.

Iron Absorption Regulation

• Intestinal mucosal cells regulate iron intake.
• Body iron stores reflect the cytoplasmic iron content of intestinal mucosa cells.
• High iron stores prevent absorption, and mucosal cells shed into the lumen.
• Low iron stores activate absorption.

Iron Excretion

• There's no physiological mechanism for iron excretion; losses are via intestinal shedding, urine, nails, hair, skin cells, and menstruation (in females). Daily losses of around 1 mg are counterbalanced by comparable daily absorption.

Body Iron Distribution

• Total body iron in adults ranges from 3.5 to 2.5 grams, higher in males than females. Most iron is in hemoglobin (65-70%).
• Iron is stored as ferritin and hemosiderin in reticuloendothelial system (liver, spleen, bone marrow) and parenchymal liver cells (25-29%).
• Tissue iron is in iron-containing enzymes and myoglobin in muscles (4%). Plasma iron is a small part (0.1%) carried by transferrin.

Causes of Blood Loss Anemia

• Gastrointestinal tract blood loss is most common in men (above 40) and post-menopausal women. Possible causes include occult malignancy, gastritis, peptic ulcers, inflammatory bowel disease, polyps, angiodysplastic lesions, or hookworm/schistosomiasis.
• In women of childbearing age, menstrual blood loss, pregnancy, and breastfeeding can lead to iron deficiency. In developed countries, a third of women have low iron stores , but only 3% display iron-deficient haematopoiesis.
• Chronic haemoptysis (coughing up blood) or haematuria (blood in the urine) rarely cause iron deficiency.
• Chronic use of aspirin or NSAIDs exacerbates intestinal blood loss due to related intestinal erosion and platelet impairment.

Malabsorption

• Dietary assessment is essential to evaluate iron intake.
• Gastric acid is required to release iron and keep it in a soluble ferrous form.
• Hypochlorhydria (low stomach acid) due to aging or medications (e.g., proton pump inhibitors) reduces iron bioavailability.
• Coeliac disease affects iron absorption in the small intestine.
• Patients with unexplained malabsorption or recurring deficiency should be screened for coeliac disease.

Physiological Demands

• Iron demands increase during rapid growth periods like infancy and puberty, potentially exceeding absorption rates.
• Factors like prematurity and breastfeeding in infants, or menstruation in girls, can exacerbate these demands.
• Pregnancy diverts iron to the fetus, placenta, and increased maternal red blood cells, leading to loss with parturition.

Diagnosis of IDA

• Hematological findings: Hemoglobin, Packed Cell Volume (PCV) reduced. MCH, MCV, and MCHC all reduced. Leucocytes and platelets usually normal. Red cells on film are hypochromic and microcytic. Bone marrow shows nonspecific changes. Depleted iron stores are seen via stain.
• Serum Iron and TIBC: Serum iron reduced, Total iron binding capacity (TIBC) increased and transferrin saturation is reduced and below 15%.
• Serum Ferritin: Reflects storage iron and is often reduced in IDA (below 15 µg/L).
• Bone marrow iron: Assessment typically utilizes Prussian blue staining, demonstrating depleted iron stores.

Differential Diagnoses for IDA

• Thalassaemia: Clinical features, iron studies, haemoglobin electrophoresis.
• Sideroblastic anaemia: Clinical features, iron studies, bone marrow iron stain.
• Lead poisoning: History, blood film, iron studies, urine lead levels.
• Anemia of chronic disorders: History, iron studies.

Management of IDA

• Oral iron therapy: Preferred treatment, typically ferrous sulphate (200 mg 8 hourly).
• Parenteral iron therapy: Employed only for malabsorption or intolerance to oral iron, often utilizing iron sorbitol via deep intramuscular injection (1.5 mg/kg body weight).
• Monitor response: Hemoglobin should increase by 10 g/L every 7-10 days. Reticulocyte response expected in a week.
• Patient counselling: Patients should be warned of possible brown skin discoloration at injection sites during therapy. Iron isomaltose and carboxymaltose preparations are now favoured due to fewer allergic effects.
• Careful investigation of IDA causes: especially to rule out pathological blood loss.
• Dose Adjustments: Potential need for dose adjustment to 200 mg 12 hourly, or switching to ferrous gluconate 300 mg 12 hourly (70 mg of elemental iron per day), may be indicated in patients experiencing intolerance.
• Body weight calculations: Body weight (kg) multiplied by 2.3 and the difference between 15 and the patient's hemoglobin (g/dL), plus either 500 or 1000 mg, can quantify the required iron stores.

Clinical Findings

• Clinical features related to underlying pathology (if any).
• Early stages of anemia typically show no significant findings.
• Signs/symptoms of severe anemia progress to pallor, fatigue, reduced exercise capacity, and shortness of breath.
• Severe cases may demonstrate mucosal changes such as mouth soreness (glossitis with a smooth red tongue), nail spooning (koilonychia), craving unusual substances such as dirt, clay, ice, salt, hair or cardboard (pica), but no organomegaly.
• Pallor of the conjunctiva.
• Glossitis (smooth red tongue).
• Koilonychia (spooning of the nails)

Test your knowledge on anemia specifically related to pregnancy. This quiz covers hemoglobin definitions, reference ranges during pregnancy, physiological changes, management strategies, and potential complications associated with anemia. Perfect for medical students and healthcare professionals.